View source for Volcanic island

{{Short description|Island of volcanic origin}}
{{Redirect|High island|places named High Island|High Island (disambiguation)}}
{{For|the GPU series|Radeon 200 series{{!}}Volcanic Islands (GPU family)}}

[[File:Moorea ISS006.jpg|thumb|[[Mo'orea]], a ''volcanic island'' where the central island is still prominent]]
[[File:Aerial image of Stromboli (view from the northeast).jpg|thumb|[[Stromboli]] is one of the eight [[Aeolian Islands]], a [[volcanic arc]] north of [[Sicily]]]]

Geologically, a '''volcanic island''' is an [[island]] of [[volcano|volcanic]] origin. The term '''high island''' can be used to distinguish such islands from [[coral island|low islands]], which are formed from [[sedimentation]] or the [[Tectonic uplift|uplifting]] of [[coral reef]]s (which have often formed on sunken volcanos).<ref>{{cite journal |last=Murphy |first=Raymond E. |date=July 1949 |title="High" and "Low" Islands in the Eastern Carolines |journal=[[Geographical Review]] |publisher=[[American Geographical Society]] |volume=39 |issue=3 |pages=425–439 |bibcode=1949GeoRv..39..425M |doi=10.2307/210643 |jstor=210643}}</ref> 

==Definition and origin==
There are a number of volcanic islands that rise no more than {{convert|1|m|0}} above [[sea level]], often classified as [[islet]]s or rocks, while some low islands, such as [[Banaba]], [[Henderson Island (Pitcairn Islands)|Henderson Island]], [[Makatea]], [[Nauru]], and [[Niue]], rise over {{convert|50|m}} above sea level.

The two types of islands are often found in proximity to each other, especially among the [[list of islands in the Pacific Ocean|islands of the South Pacific Ocean]], where low islands are found on the [[fringing reef]]s that surround most volcanic islands. Volcanic islands normally rise above a [[hotspot (geology)|hotspot]] or [[subduction zone]].

==Habitability==
Volcanic islands usually range in size between {{convert|1|and|104|sqkm|sigfig=1}}.<ref>{{Citation |last=Condie |first=Kent C. |title=Chapter 2 – The crust |date=2022-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780128199145000111 |work=Earth as an Evolving Planetary System (Fourth Edition) |pages=9–37 |editor-last=Condie |editor-first=Kent C. |access-date=2023-12-28 |publisher=Academic Press |isbn=978-0-12-819914-5}}</ref> Islands above a certain size usually have fresh [[groundwater]], while low islands often do not, so volcanic islands are more likely to be habitable.

Many volcanic islands emerge from the deep abyss of the ocean, and feature rough or mountainous landscapes in their interiors and a diverse array of summit elevations. Researchers have observed that the island will often be covered by dense tropical forest. These limit settlement on the interior of many islands, forcing communities to develop along the coast.<ref name=":0">{{Citation |last=Velmurugan |first=Ayyam |title=Chapter 1 – The Nature and Characters of Tropical Islands |date=2008-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780128130643000016 |work=Biodiversity and Climate Change Adaptation in Tropical Islands |pages=3–30 |editor-last=Sivaperuman |editor-first=Chandrakasan |access-date=2023-12-28 |publisher=Academic Press |isbn=978-0-12-813064-3 |editor2-last=Velmurugan |editor2-first=Ayyam |editor3-last=Singh |editor3-first=Awnindra Kumar |editor4-last=Jaisankar |editor4-first=Iyyappan}}</ref> Larger islands may have rivers, resulting in flood hazards. Rivers deliver sediment downstream, which can dominate the shape of the coast and contribute to erosion. Tall volcanic islands are often surrounded by protective fringing or barrier reefs, creating lagoons.<ref name=":0" />

The unique geological and geographical characteristics of volcanic islands make them prone to many natural hazards, which are expected to worsen due to [[climate change]]. These include volcanic eruptions, earthquakes, tsunamis, landslides, and severe weather events like hurricanes or typhoons. Studies have highlighted the importance of implementing effective risk mitigation plans that include nature-based solutions to improve societal safety on these islands. These involve leveraging natural processes and ecosystems to reduce hazard impacts. This can include the restoration of natural barriers like mangroves or coral reefs that protect against tsunamis and storm surges or the maintenance of natural water catchments that can mitigate flood risks.<ref>{{Cite journal |last1=López-Saavedra |first1=Marta |last2=Martí |first2=Joan |last3=Planagumà |first3=Llorenç |date= 2023|title=How Effective Risk Assessment and Management Is the Key to Turning Volcanic Islands into a Source of Nature-Based Solutions |journal=Land |language=en |volume=12 |issue=3 |pages=686 |doi=10.3390/land12030686 |doi-access=free |issn=2073-445X}}</ref>

==See also==
{{Portal|Islands}}

*{{annotated link|Archipelagic apron}}
*{{annotated link|Atoll}}
*{{annotated link|Canary Islands}}
*{{annotated link|Galápagos Islands}}
*{{annotated link|Guyot}}
*{{annotated link|Krakatoa Archipelago}}
*{{annotated link|Seamount}}
*{{annotated link|Submarine landslide}}
*{{annotated link|Volcanic arc}}

==References==
{{reflist}}

== External links ==
* [http://www.britannica.com/EBchecked/topic/380461/Micronesian-culture/276610/High-island-and-low-island-cultures ''Micronesian culture: High island and low island cultures'' at Britannica.com.] Retrieved 2011-09-22.

{{Earth's landforms}}

[[Category:Islands by type]]
[[Category:Volcanic islands| ]]